FIG 3.

MMP-9 facilitates HBV replication in a HepG2-NTCP infection system. (A) HepG2-NTCP cells were mock infected or infected with HBV at 1,000 GEq for the indicated times. MMP-9 mRNA levels were measured by qPCR. (B and C) HepG2-NTCP cells were transfected with the vector or pCMV-Tag2B-MMP-9. Twenty-four hours later, cells were infected with HBV at 1,000 GEq. (B) HBeAg levels in the supernatants of infected cells at the indicated times were determined by an ELISA. OD, optical density. (C) The levels of HBV 3.5-kb RNA at 6 days postinfection (dpi) were measured by qPCR. (D to G) HepG2-NTCP cells were transfected with sh-Ctrl, sh-MMP-9-1, or sh-MMP-9-2. Twenty-four hours later, cells were infected with HBV at 1,000 GEq. (E) HBeAg levels in the supernatants of infected cells at the indicated times were determined by an ELISA. (D and F) The mRNA levels of MMP-9 (D) and HBV 3.5-kb RNA (F) at 6 days postinfection were measured by qPCR. (G) The expression of HBcAg in cells was analyzed by immunostaining at 8 days postinfection. Graphs show means ± standard deviations (n = 3). *, P < 0.05; **, P < 0.01; ***, P < 0.001.